Bicondylar Intraarticular Humeral Fracture

Bicondylar intraarticular fractures (also known as bicolumn fractures) of the distal humerus make up only 1% of distal humerus.

Distal humeral fractures are classified into three broad categories by the Müller Arbeitsgemeinschaft für Osteosynthesefragen (AO) system. Each category is further divided into 3 subcategories, and each into 3 sub-subcategories, giving a total of 27 types!

• Type A: Extra-articular - No involvement of displaced fractures extending into the articular surface
• Type B: Partial intra-articular - Part of the articular component is involved, leaving the other part attached to the metaphysis or diaphysis
• Type C: Complete intra-articular - Articular surface is involved and the metaphyseal fracture completely separates the articular component from the diaphysis.
  • C1: Articular simple, metaphyseal simple
    • C1.1: Slight displacement
    • C1.2: Marked displacement
    • C1.3: T-shaped epiphyseal
  • C2: Articular simple, metaphyseal multifragmentary
    • C2.1: With an intact wedge
    • C2.2: With a fragmented wedge
    • C2.3: Complex
  • C3: Articular multifragmentary
    • C3.1: Metaphyseal simple
    • C3.2: Metaphyseal wedge
    • C3.3: Metaphyseal complex (current case)

Our case is a type C3.3 fracture. There are two fracture planes through the articular surface (better seen on CT), making this an articular multifragmentary fracture (C3). Multiple metaphyseal fragments are seen, making this a metaphyseal-complex fracture.

The full range of fractures can be found at the OA web site (see below). Another classification scheme, the Jupiter system, is also used.

References

OA Classification